MAGNETIC RESONANCE INVESTIGATION OF THE MAGNETIC TRANSITION IN TDAE-C60

Abstract

The ESR and NMR lines in powder samples of TDAE- C ₆₀ do not show the expected frequency shifts due to long range ordering in the low temperature magnetic phase, but instead show only a relatively small line broadening below T_c=16 K. The temperature dependence of the lineshapes in ESR, the absence of a spontaneous magnetization as well as other magnetic properties suggest that the magnetic ordering below T_c=16 K is local and random, i.e. spin-glass like, rather than ferromagnetic. The possible finite-particle-size effects and possible microscopic mechanisms for the observed magnetic behavior are discussed.